On-Off Keying (OOK) is a popular wireless transmission modulation method which is widely used in remote controls for car alarm systems, wireless home alarm systems, remote controls for garage door openers, and wireless home automation devices. In contrast to other wireless transmission techniques, such as Frequency Shift Keying, Frequency Hopping Technology, and Spread Spectrum Technology, which are used in many wireless applications (e.g., Wi-Fi™, Bluetooth™, cordless telephones, etc.), OOK is considerably less complicated and hence less expensive. OOK may be used in wireless communications where the amount of data transmission is limited, such as remote control for garage door openers. For wireless communications requiring limited data, such as garage door openers, complicated wireless data transmissions or protocols is not necessary. Thus, in order to provide a low cost solution, these applications employ a signal encoded with the identification number of the remote. Receiving the signal carrying the identification number will cause the garage door opener to actuate the opener.
While OOK is known for use in less complicated wireless transmission applications, there still exists a need to provide secure transmission of data without significantly impacting the cost of such systems.
Encryption for wireless signals has been used for years. One of the most popular encryption methods for wireless transmission is rolling code technology (RCT). RCT is implemented into both transmitters and receivers, such that a current data transmission is different from each previous data transmission. This is typically accomplished by having a specific rolling code algorithm built-in to both the transmitter and receiver. Based on the signal received from the transmitter and the specific rolling code algorithm, the receiver calculates the next code to expect. This is designed to minimize the danger of capturing a previously-transmitted code and re-transmitting it at a later time for unauthorized access.
While RCT has been used for many years for wireless transmission applications, additional encryption is always desired. It is desired that with additional encryption, cost will not be increased significantly. Therefore, there is a need for an improved wireless communication protocol with enhanced degree of security over present technology without significantly impacting the overall cost of the transmission system.